Running gear for flat/step

475/500 HP, 3.55s and a 13... Should be good for whatever you pull on a flat. With 3.36s, I would want more HP....525,550,565hp minimum. If you are secretly planning to pull oversized, start with a minimum 475/500hp, 13 speed and 3.70's or 550 hp 13-18 speed with the 3.55 or 600 hp with 3.36s (18 speed will be the only transmission you find with a 600 hp engine.).

Do you have a specific truck in mind yet?

 

If he ever wants to get into 100k lbs plus, those gears (3.36 and taller) will be a pain in the rear, literally.
3.55 is a MINUMUM for pulling weight, or running the North West a lot.
I can run whatever speed in my truck, it makes next to no difference when over 100k lbs and wide and tall. The truck also makes next to no difference. My WS got the same MPG as a Crapcadia, same motor/tranny/gearing/loads/trailers/routes.
So yeah, ask me what my fuel cost is per mile when I go by you and you catch me up, and I will tell you to the tenth of a penny if you like. Not everyone chases the almighty (and imaginary in most cases) 7+mpg. Hauling some stuff, it just wont happen regardless.
If I am chasing a sunset, curfew, crane appointment, or just plain feel like it, I will run the speed limit all day long in ND etc. If you want to whine at me at the truckstop that night, go ahead....just be prepared to get laughed at, along with some firm facts to back up my laughter.
Not everyone has the freight hauler mentality, and some of us have been out here longer than just a few (3 IIRC) years, running our own trucks for pretty much all that time.
Rant off

Martin

 

Maybe you didn't read it try again...

Like I said my truck gets better fuel economy at 70mph in 13th than it does at 60mph at 1250rpms and if I want my fuel economy back up I have to drop a gear....this is watching the scan gauge live feed.

 

They say, "I would hate to have your fuel bill."
We say, "I would hate to have your income."

Martin brought up an interesting topic. You mentioned flatbed, so I was thinking of 80000 lb GVW. I don't know your future plans, but you can kill 2 birds with one stone if you decided to buy a 3 axle step (can't see you pulling too many 100000lb loads with a 5 axle setup). If you did want to consider pulling the bigger oversized loads (it doesn't have to be heavy, 13ft or wider plus a headwind will kill you if you're not spec'd right), consider a 3.70 gear with your big engine. 3.70's will still let you boogie down the highway, And give you enough gear to change the rotation of earth.

On the sticker in the drivers side doorjam, you will see a transmission code that will go something like RTLO189X18A. The first set of numbers is the torque rating, the second set will be how many forward gears the tranny has. A 13 speed will have either 1650ft lbs or 1850. The 18s will have either 1850 or 2450 torque. You want the bigger number. The heavier duty truck's components will match, clutch, radiator, rear axles...etc. ANDit should have the full gauge package, transmission oil temp, a temp gauge for both rear gears, and a Pyrometer.

 

72 is good enough for me unless its time to go home....

 

Thanks for your service comrade... I did two tours in Iraq; 04/05 & 09/10 I started driving truck in 08...you are not lieing about how them sob's drive over there, at least in Iraq. There are 3 things they do not use, brakes, mirror's and roads,,,,lol

 

I have a 2012 Coronado midroof, glider... it has the S60 12.7 with 535hp (what I was told by Fitzgerald). I have 3:55 gears I have the 12K front axle and 20K rears. I have a 13 single over with 22.5's At 67mph my rpm's read 1425 in 13th. At 57 it reads 1425 in 12th At 71mph, in 13th, it runs 1500rpm's. Same with 61mph in 12th. I have the full gauge package, which includes boost, pyro, rear axle temps and trans temp gauge. I pull a reefer right now but, plan to pull a step in the near future. I cant find a tag that states what torque my trans has but, I will call Fitzgerald Monday. What I love about my glider is; no egr, no dpf and no def....

 

I would agree with most of what you said. But I've never heard of a trans rated for 2400pounds of torque.....

http://www.roadranger.com/ecm/idcpl...ed&Rendition=Web&md2psid=2-139734154895923968



18 speeds come in 1850, 2050 or 2250. The rumor I've always heard is it's the same tranny with a little different oil bath system.

Most guys around here get the 1850 and stuff a 2050 clutch in front of it.


but I've been wrong before .........